The New Dynamic Duo
by A. Zap
Summary: Dean and Sam go missing while on a case. Therefore, it's up to Charlie and Castiel to find out the truth. They find that they get along even better than they thought. For Charlie.


**DISCLAIMER: Is Charlie still alive on Supernatural? She isn't? Then, obviously I do not own Supernatural.**

* * *

The New Dynamic Duo

"I require your assistance." Castiel's voice thrummed down the phone line, a low vibration in her ear.

"Okay, what's up?" Charlie held the phone up with her shoulder as she returned the gas nozzle into its cradle.

"I'm in Cedar Falls, Iowa." He gruffly said, though Charlie had found that he always sounded like that. "Dean and Sam were investigating a string of mysterious disappearances here and asked me to come assist. However, when I got here, they had disappeared themselves." He paused. "I would appreciate it if you helped me."

"Really? I mean," Charlie was glad to help but she didn't want to intrude where she wasn't wanted, "you've been doing this for years, right? And you were apparently human for a while. I'd be glad to come but do you really need me?"

"This will require extensive…talking to people. According to Sam and Dean, my skills when it comes to deception still are sub par." It surprised Charlie how disgruntled he sounded about that. "Since meeting you, I've noticed that your people skills are quite often even better than the Winchesters'. Also, you're care for them is wonderful to see. I can think of no person I would rather trust."

Charlie felt herself blush a little at the compliments, but she didn't try to stop the wide grin that spread across her face. "I'm actually just a few hours away. I'll get there soon." She slid into her car and strapped herself in. "Any specific destination?"

"I've reserved the room next to theirs; we can meet here. It's the Emerald Tassel Motel, room 113." Cas paused again. "Thank you."

Charlie smiled again. "You're welcome. See you soon." With that, she hung up her phone.

She quickly turned the keys, her car coming to life, and soon she was roaring down the highway.

Despite the seriousness of the situation, she couldn't wait to get to know Castiel better.

* * *

Castiel breathed a sigh of relief as Charlie pulled into the parking spot next to his. He had been quietly fretting ever since he had got here and found the motel room empty. After subtly asking around in order to not draw attention and calling their cell phones repeatedly, he had come to the conclusion that whatever they had been hunting had taken them as well. It left a lot of options open as to what it was and he had really needed an ally. He was glad that Charlie had come.

"Hey, Cas!" Charlie stood up out of her car with a bright smile and wave.

"Hello, Charlie." Cas said, and to his surprise, Charlie walked over and hugged him. He wrapped his arms around her briefly before she pulled away.

"So, lead the way." She gestured for him to open up the room's door. Together, the two entered the room and Charlie set her things on the bed next to where Castiel had put his own things. She then turned and joined Castiel at the table where he had put all of the boys' research. "What've we got?" She asked as Cas shuffled the papers into a semblance of order.

"Students from the local college have been going missing." Cas pulled out several articles out from the pile. "If you would look at my laptop," he nodded at it as the nerd clicked it open and looked at the map and diagram he had made, "all of these people have disappeared near the river that runs through this town. There was no trace of struggle from Sam's notes." He pulled out the relevant research notes.

"Hmm." Charlie chewed her lip a bit as she looked from the articles to his computer. Moving over to the bed, she grabbed her own tablet and set it up. "Any similarities among the victims?"

"I do not know besides the fact they attended the same education institution." Cas was flipping through the notes and case files. "If they had found something, they didn't write it down. The students were of different ages and cultural backgrounds. Several of them were not even locals and lived in the dormitories."

"Right." Charlie nodded and Cas looked over to see that she had somehow gained access to the students' school records. She then looked up into his eyes. "What makes you think that this thing took them?"

"I located the Impala here." He pointed out a spot on the map, near the river just like the other victims. Charlie made a small sound of understanding. They both knew that Dean would never leave his precious car behind or out in the open. Wherever the Impala was was generally a good indication of where Dean was. "I left it there as Dean has shown doubt in my driving abilities."

"Dang." Charlie grimaced. "Did they even know what they were facing?"

"If they did, they didn't write that down either." Cas admitted, a bit peeved that the boys' would leave so few clues.

Charlie nodded again. "Okay." She clapped her hands together. "Let's look through my monster database." She pulled up the app she had created.

Intrigued, Castiel leaned in closer to get a better look.

* * *

Charlie stifled a laugh at the curious expression on the angel's face. She had read the books, but she had never realized exactly how adorable Castiel could be. At least he lived up to the description of dreamy, but she had never had any doubts about that.

"You created this?" He asked, visibly impressed as he tapped on one of the pictures and all of the information regarding the creature popped up.

"Yeah, based of the _Supernatural_ books and my own experiences with the Winchesters." She sat back as Castiel exited the chosen creature.

Cas smiled a bit. "That is how the Winchester Gospels were meant to be used." A hint of admiration crept into his voice. "Yet to utilize it this way and to convert into the most common format of this era," he looked up at Charlie, "this is phenomenal."

Charlie grinned and blushed a bit. Sure, the Winchesters had made it clear that they thought highly of her capabilities. Still, there was nothing like the compliments and admiration of an angel of the Lord. And of all angels, this was Castiel.

It was no wonder she felt flattered.

"Anyway," Charlie waved a hand, pushing the compliment aside, "let's see if any baddies on this list match up."

It didn't take them long to eliminate most of the creatures on the list. It didn't seem to be a ghost, and the circumstances weren't right for most things that the Winchesters had faced before. Also, the two hoped that the boys' would recognize something that they had faced before.

"The most likely causes from what we know," Charlie summed up, "is a djinn, siren, water spirit, or heck, maybe a Leviathan."

"From what they have faced before." Castiel pointed out, though he had stiffened up a bit at the mention of Leviathan. "It could be a water based creature. I can think of several possibilities in that direction."

"We need more info on the victims." Charlie scratched her head a bit. "Okay." She stood and stretched. "Do you have a badge?" She glanced over at him.

"Yes. Dean gave me one a long time ago." Cas pulled it out and handed to her. She looked down at the badge for one Eddie Moscone.

"Nice." She tried to stifle her laughter. Once more, Dean's tastes were shining through. And then she realized that this was _the_ badge. "Wait." She looked up. "This is the one given to you when you guys were going after Raphael, right?"

Cas looked a tad bit embarrassed. "Yes."

"Wow." Charlie gazed down at it. "I'm impressed it's survived so long."

"Well," Castiel took it back and gazed down at it, "Dean gave it to me."

Charlie hid a smile. He was just so cute! "Here," she pulled out her bag, and pulled out some new badges for him. "I made these after we met. Just in case you want some variety."

Cas peered down at them curiously and Charlie knew the names he was seeing: Steve Rogers, Neville Longbottom, Rory Williams, Clark Kent, and several pop culture wonders. "Thank you. I will surely use these in the future." He tucked them into his duffle. "However, I shall use this one for now."

"Okay." She had expected it. She showed her own ID. "I'm Agent Granger." He read what hers said quickly. "Just give me a few moments to change." He nodded.

"I'll be waiting in the car." He walked through the door, almost seeming eager to get out before she changed.

Charlie subdued another laugh and got to switching her outfit.

This was turning out to be a lot more fun than she had thought.

* * *

"I'm Agent Moscone. This is my partner, Agent Granger." Castiel said in a tone that brooked no argument, because this was serious business. He pulled out his badge and flipped it open as Charlie did the same by his side.

He froze a moment as he realized that it was upside down once more. In his mind's eye he once again saw Dean reaching over and exasperatingly turning it the right way up. Why could he never seem to get this part right?

Castiel risked a glance over a Charlie hoping she hadn't caught his mistake and blinked. Charlie was similarly frozen and also holding her badge upside down. She peeked at him a bit, as if seeing if he had caught her own mistake, but then surprise filled her eyes when she saw him.

For a second, the two of them looked at each other, and Cas would bet that she was also trying to suppress a relieved smile.

This happened within a few moments as Cas snapped his attention back to the officer before him.

"Of course, agents." The police officer replied, not seeming to care about their faux pas. "How can I help you?"

"We are here to look into the disappearances that have occurred in this city." Cas continued confidently. Things were going well so far.

"Really?" The officer was surprised. "I could have sworn there were two of your guys already on this."

Cas's mind blanked. He had no idea how to respond to that. "Uh…"

"Not our division!" Charlie blurt out suddenly, making Cas jump a bit. She smiled nervously as they both turned to look at her. "I mean, they're from a regional branch. We're a bit higher up, and they, uh…"

"They have failed to check in, so we were sent to assist and make sure everything is all right." Cas covered for her. After all, that was mostly true. He sent a grateful glance at her anyway for coming up with the idea. She, for some reason, returned it.

"Oh, I see." The officer offered a strained smile. "Is there something you want to know that's not in the files you already received?"

"Yes," Charlie nodded, "was there anything else in common besides going to the same college? There didn't seem to be anything in the files, and we haven't seen our colleagues to learn what they know. We thought we would stop here before going to the college."

"Actually, yeah." The officer said. She pulled out some notes from below the desk and flipped through them. "We of course interviewed the friends and relatives after the victims had disappeared. All of them seemed to be huge partiers. The river's a popular spot around here to get away from the campus and for the kids to binge. We would think that these people had fallen in and drowned on accident except there's been no trace of them." She looked up. "Does that help?"

Castiel could feel several of the facts coming together in his mind. There was just one thing that he had to check. "As a result of these parties, was any waste ever thrown into the water or littered the shore?"

The officer grimaced. "Unfortunately, yeah. We used to have a program that would clean all of that up and take care of it, but…" She shrugged. "Budget cuts."

That settled it. "Thank you for your time." Castiel gave her a final nod and turned to leave.

"If you find anything else, here's my card." Charlie handed a business card to the officer before trotting after the angel.

As they reached his car, she lowered her voice. "Do you know what it is?"

"I think so." Castiel said as they both slid in. "We'll discuss it back at the motel."

* * *

"I believe this is the work of a naiad." Castiel declared just as Charlie was getting settled behind her tablet on her bed.

"Like the nymph from Greek myths?" Charlie asked in confirmation, quickly looking up naiads.

"Yes, although nymphs are not as promiscuous as the tales make them appear. A naiad is the type of nymph that lives in fresh water." Cas confirmed.

"So one's living in the river?" Charlie connected the dots. She flipped through the files and saw that obviously something water related was going on here, especially if the river was being polluted.

"I believe so, though I have never heard of a naiad living outside of the Mediterranean or Europe." He frowned as he gathered up the evidence himself.

"I'm guessing you haven't read the Percy Jackson series then." Charlie commented off-handedly while scrolling through several web pages regarding nymphs and naiads.

"The what?" The angel looked up with a tilt of his head.

"It's a book series. And as far as anyone is concerned that's all that exists in relation to Percy." Charlie felt her voice darken at that second sentence, but she couldn't help it. The movies were not all that great, even if Nathan Fillion was Hermes.

"I suppose it's not something Metatron read." Cas shrugged his shoulders and moved on back to the topic. "In any case, naiads to not require sustenance, though local peoples would occasionally offer sacrifices to them. It's unlikely that this one has eaten any of the victims."

Charlie raised an eyebrow. "I'm sensing a but here."

"Indeed." Cas gravely said. "Naiads are as protective of their homes as anyone else. Litter in her territory would not be looked upon well. As long as the city was taking care of it, she was fine, but as that stopped." He winced. "This probably a punishment that she is meting out for defiling her home."

"Why take Dean and Sam though?" Charlie frowned, as they would not have been part of such shenanigans. Well, Sam probably wouldn't.

"If they approached her to try to kill her, I'm fairly certain she would take offense." Cas summed up.

"Yeah, I guess I would too." Charlie looked up from the screen. "I'm not finding anything on how to kill one."

"Most people would not try to kill them as they were seen as lesser spirits and local deities." Cas said matter-of-factly. "Even if Sam and Dean had realized what their foe was, I doubt they would have realized the method for killing her."

"Do you know?" Charlie really hoped he did.

"Yes. I can think of two methods." With a flick of his wrist, Castiel's angel blade slid into his hand from his coat sleeve. Charlie gazed at it in amazement. She had read about it and heard about it from the Winchesters, but it was something to see a blade appear when there had been no signs of it moments earlier. "My angel blade can dispatch most creatures. Another option would be to take a bronze sword or knife, dipped in salt water, and stab them in the heart." He paused. "Coincidentally, nereids, their sea counterparts, are killed through the same method, only the blade must be dipped in fresh water."

"I'm guessing that the boys have several bronze daggers in the Impala." Charlie smiled, glad that they were in the right direction.

"Yes," he tilted his head as a thoughtful look crossed his face, "though I believe that should be our second option. Perhaps we could try to talk to her first."

"Gotcha." She stood and stretched. "When do we leave?"

* * *

Castiel parked next to the Impala and both of them got out. With a wave of Cas's hand, he easily used his Grace to unlock the trunk. After some shuffling around, the Winchesters' bronze knife was found and dipped in the salt water Charlie had made in the motel.

"All set here then." Charlie slid the knife into its sheaf and tucked it into the back of her jeans. It saddened Cas a bit that just a few years ago she had been a normal citizen and now she was really a hunter. That seemed to happen a lot around the Winchesters. "Now what?" She asked as she looked up at him.

"We'll go down to the river and ask for an audience." Castiel told her, and they made their way down.

It was a pleasant enough sight, and deserted enough that it was easy to see why college kids would use it as a place to party. Reaching out with his senses, Cas could feel that some sort of supernatural entity had been there. Now, he just had to call her out.

Stepping up to the river, he crouched down and swirled his hand in the water. In Greek, he said, "Spirit of this river, heed our plea. We seek an audience with you, as you will."

There was silence as Cas straightened. Only the chirping of crickets could be heard in the distance. Then, the water swirled and figure began to rise from it. He heard Charlie gasp beside him.

Of all water creatures, nymphs, whether a naiad or nereid, were without a doubt the most aesthetically pleasing. And they were like that naturally, as some creatures, like the siren, was able to create illusions of beauty. There were reasons why in many Greek tales, nymphs were pursued by both gods and mortals.

This particular one was as beautiful as the rest of her species. The naiad's hair flowed down her back, green and crinkled with leaves like algae. Her skin was a pale blue, and her eyes were a darker blue that shifted like moonlight on a pond. She barely wore enough clothes to be considered decent, which appeared as light as the foam that came upon rapids and was dotted with pebbles and shells. All in all, she clearly showed off her curves as she rose forth from the water, her feet still appearing to merge with the water, and threw back the hair that had fallen into her face with a flip of her head and wrist.

Castiel stood and watched all of this, but remained unaffected. After all, he had seen sights just as beautiful if not more so in his time. Dean's soul was definitely more wondrous. A glance at his companion, however, told him that Charlie was quite taken with the naiad's beauty. A slight nudge with his elbow knocked her out of it though. She threw him a sheepish look before turning her attention back to the naiad.

"What may I do for you, angel?" The naiad's voice danced like water over stones.

"We ask that you return the people that you have taken." Castiel came out and said. "Especially two men that came here a few nights ago."

She frowned. "No." She stubbornly replied, and her face darkened at his request. "Those mortals deserved it as they defiled my home and made no attempt to clean up after themselves. As for the men," with a snap of her fingers, Dean and Sam appeared in the river, enclosed within bubbles but seemingly unhurt, "they were quite rude. They tried to stab me with silver." She wrinkled her nose. "What on Earth were they thinking?"

"They most likely weren't thinking very well." Charlie admitted. She smiled at the naiad and her eyes took on a look that Cas recognized from when Dean went to bars seeking companionship for a night. "Understandable, as one look at you could make any other thoughts disappear."

A faint blush rose up in the naiad's cheeks. As Cas had told Charlie earlier, nymphs were not as promiscuous as the tales said, but they could be flattered and they loved a good lay. Castiel looked between the two as Charlie followed it up with a wink.

"Are the humans actually harmed?" Cas looked down at where Dean and Sam were, but it seemed that they were merely in an enchanted sleep.

"No." The naiad dragged her eyes away from Charlie. "I am holding them in suspension until I come up with something or the mortals cease their parties."

"How about we make a deal?" Cas offered and Charlie gave him a sharp look. He held up his hand to placate her. "I will make arrangements that the area will once more be cleaned up. I hardly think the students will cease their behaviors, but the results of such actions will ensure that your home remains pure."

The naiad thought about it. "That would be acceptable."

Cas nodded, glad that she had been appeased. It would take a bit of his "mojo" to make everything work out, but a peaceful conclusion was really for the best.

"However," the naiad placed her hands on the Winchesters' bubbles, "these mortals attacked me. I cannot let them go so easily."

Castiel frowned unsure what to do at this point. There wasn't much he could do for make up for the Winchesters' attack.

"I've got an idea." Charlie gave that coquettish smile again. "How about you let them go," she stepped closer to the river's edge, "and I'll _personally_ make it up to you?"

The naiad studied Charlie for a moment before smiling. "It's a deal."

Cas and Charlie both gave sighs of relief. They shared a smile as the missing college students appeared on the shore, and the Winchesters were released. Charlie made arrangements to meet up with the naiad just as the two woke up.

* * *

"Wow, good job, I guess." Sam said as he took a long sip of his coffee. "We weren't actually sure what it was. We went to check out the spot and when she revealed herself, we figured that silver usually works."

"You offered to go on a date to rescue us?" Dean asked incredulously, sounding a bit jealous. "I thought you knew better than to get close to supernatural creatures."

Charlie gave Dean a dry look. She glanced at Cas next to her and gave a large, fake gasp. "Oh, no! I'm sitting right next to a supernatural being! Whatever shall I do?"

Cas lips twitched up into a smile, but Charlie saw him trying to hide it by taking a sip from his own drink.

"Yeah, well, Cas is different." Dean gruffly said.

Charlie rolled her eyes. "Come off it, Dean. You ruined Gilda for me, you are not screwing up my chances with a naiad."

Castiel gave her a quizzical look so Charlie mouthed, "I'll tell you later," at him. He seemed satisfied with that.

"Still, it's nice to see you guys getting along." Sam commented.

"Yeah, but don't let this get to your heads." Dean pointed a warning finger at them, trying to hide his concern. "I don't like you guys hunting on your own."

Cas frowned, clearly unimpressed by Dean's attitude. "I have fought evil for millennia, and I often have traveled and fought on my own. I do not see how you could stop me from continuing."

"Right. Besides, we weren't on our own." Charlie smiled as she threaded her arm into the crook of Castiel's elbow. "Watch out, Winchesters! You're looking at the new Dynamic Duo!"

As Dean spluttered and tried to find a response to that, Cas tilted his head with a thoughtful expression. Then, he turned to Charlie. "Does that make me Batman?"

Charlie and Sam roared at Dean's indignant expression. After all, since when did Castiel make references, especially towards Dean's favorite superhero? However, Cas just gave a small smile.

As the laughter died down, Charlie threw her arm around Cas's neck. "Cas, I think this is the beginning of a beautiful friendship."

And as Cas smiled back at her, Charlie truly believed that.

* * *

 _AN: So the moment I saw Cas and Charlie meet I thought, "Move over, Sam. I've got a new BroTP for Supernatural." Then, naturally, Supernatural killed it two episodes later. This is for Charlie. Also, those reading this may also recognize this as the first chapter for a fic I'll post later. That will be "The Adventures of Charlie and Castiel." It's be a collection of one-shots that I'll write as the ideas come. It will be all of the things that I wish Charlie and Cas had done together. So be on the look out for that coming. Probably won't be up for a few days though._

 _EDIT: Okay, so this is now a stand alone but it goes along with a fic I've written called, "The Adventures of Charlie and Castiel." This is full of short stories about Charlie and Cas. Basically things I wish would would have happened though most would probably have not been shown. THIS IS SEPARATE THOUGH. I will not post those stories here but in the story of the above title. If you liked this, please check it out.  
_


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